Fianna Fáil has said it is working off the Department's projections that €8.6bn will be available for the next five years to deliver on election promises.

Mr McGrath expressed concern that the public will be left completely confused by the various figures being thrown out by parties during the campaign.

He accepted that the Fiscal Advisory Council has said there is €3.2bn at the disposal of the next government.

"As a country, we are now entering in a vital election campaign with a €5.4bn difference between the Fiscal Advisory Council's estimate of fiscal space available to the next government and the Department of Finance's estimate," Mr McGrath told reporters.

"This Government has brought the whole issue of broken promises to a new level," he added.

Mr McGrath emphasised that his party is merely outlining a "package" which it would intend to implement and insisted Fianna Fáil is taking a conservative approach with its economic projections.

There has been widespread confusion over the level of money at the next government's disposal with different projections being given by the Department of Finance and the Fiscal Advisory Council.

He said if the economic projections end up being wrong, Fianna Fáil will prioritise vital public services. Fianna Fáil intends to achieve a 60:40 split in terms of spending and tax cuts and will outline its overall economic plans next week.

But Mr McGrath ridiculed Fine Gael's plan for a €2.5bn 'rainy day' fund, saying it appeared more like a "slush fund".

The Cork South Central TD said a properly functioning 'rainy day fund' is one that is put before the Government's use, unless there is an economic slow-down.

Fianna Fáil has said that its own 'rainy day' fund will come from any "windfall" generated by surplus corporation tax receipts.

Meanwhile, both Mr McGrath and his party colleague, Senator Thomas Byrne, have completely rejected suggestions that Fianna Fáil would be willing to support a minority Fine Gael government.

"Five years ago, Enda Kenny told the people of Ireland that 'Paddy likes to know'. Now he's saying that Paddy can't know. The leader of all the Paddies is Enda Kenny, and he doesn't know," the Meath East senator said.

"He's out of touch and I believe he'll be out of office," Mr Byrne added.